That night Jock dreamed of water cows, and clans dressed in kilts, and when Sandy appeared the next morning, his head was still buzzing with wild schemes of adventure.

“Come awa’, Sandy,” he said, “let’s explore.  We’ll go up the burn and see if we can’t find out where it begins.”

“What’ll we do for lunch?” asked Sandy, who was practical.  “I brought a scone with me-but it’ll never be enough for two.”

“Ho!” said Jock.  “If Rob Roy and all his men could live in caves all the time and take care of themselves, I guess we can do it for one day.  We can fish, and maybe we might find some birds’ eggs.  I’m not afraid.”

“What about Alan?” asked Jean.

“If he comes to play, tell him to follow us right up the burn and keep whistling the pewit’s call three times over, and if we don’t see him, we’ll hear him,” said Jock.  “There’s no danger of not finding us if he follows the water,” and he and Sandy set forth at once.

Jean had finished her work and was wondering what to do with the long day which stretched before her, when Alan came running up the hill and burst into the kitchen.

“Look here what I’ve got, Jean,” he said, thumping a parcel down on the kitchen table and tearing it open.  “Eppie put this up for me.”

Jean looked and there was a whole pound of bacon, three big scones, and a dozen eggs.  “Save us!” cried Jean, clasping her hands in admiration.  “What will you do with it all?”

“I’ll show you!” said Alan.  “Where’s Jock?”

“He and Sandy have gone up the burn, exploring,” said Jean.  “They said you were to follow, and if you didn’t find them, keep whistling the pewit’s call three times till they answered you.”

“What is the pewit’s call?” asked Alan.

“Michty me!” said Jean.  “Think of not knowing that!” She pursed up her lips and whistled “Pee-wit, pee-wit, pee-wit.”

“You see, we don’t have them in London;” Alan apologetically explained, “unless it’s in the Zoo; but I say, Jean, aren’t you coming, too?  You’re as good as a boy any day.  Come along!”

“All right,” said Jean.  “I wanted to dreadfully.  I’ll get a basket for the lunch.”  She went to the closet and brought out a basket which her father had made out of split willow twigs, packed the lunch in it, and off they started.

They passed the place where the fish-bones were buried, and the spot where Alan had fallen into the water the day before, and then plunged into the deep pine forest which filled the glen and covered the mountain-sides.  The pine-needles lay thick on the ground, and above them the pine boughs waved in the breeze, making a soft sighing sound, “like a giant breathing,” Jean said.  The silence deepened as they went farther and farther into the woods.  There was only the purring of the water, the occasional snapping of a twig, or the lonely cry of a bird to break the stillness.  It was dark, too, except where the sunshine, breaking through the thick branches overhead, made spots of golden light upon the pine-needles.

“It’s almost solemn; isn’t it?” said Jean to Alan in a hushed voice.  “I was never so far in the woods before.”

“I wonder which side of the burn the boys went.  If we should take the wrong side, we might not find them,” said Alan.

“Let’s whistle,” said Jean.  She puckered her lips and gave the pewit call, but there was no answer.

“Perhaps they didn’t hear it because the burn makes such a noise.  It keeps growing louder and louder,” said Alan.

Whistling and listening for an answer at every few steps, they climbed over rocks and fallen trees, keeping as close as possible to the stream, until suddenly they found themselves gazing up at a beautiful waterfall which came gushing from a pile of giant rocks reaching up among the topmost boughs of the pines.

“Oh, it’s bonny! but how shall we get up?” cried Jean.

“We must just find a way,” said Alan.

“It’s a grand place for robbers and poachers,” said Jean, looking fearsomely at the cliffs stretching far above them.  “Angus Niel says the forests are full of them.”

“I’d as soon meet a poacher as Angus Niel himself,” said Alan, laughing, “but I’m not afraid as long as you’re with me.  It’s Angus that’s afraid of you, Jock says.”

Jean laughed too.  “I’m not afraid when I’m in my own kitchen, but it’s different in the woods,” she said.

Alan had been nosing around among the rocks as they talked, getting nearer and nearer to the fall, and now he suddenly disappeared, and for a few moments Jean was quite alone in the woods.  Soon Alan reappeared from behind the fall itself and beckoned her to follow him.

Jean was looking at the wall of rock which loomed above them.  “Sal!” she remarked, “we’ll be needing wings to get up there, or we’ll smash all the eggs for sure.”

For answer Alan popped out of sight again behind the fall, and Jean, following closely in his wake, was just in time to catch sight of his legs as he dived into a hole opening into the rocky wall.  The cliff from which the water plunged overhung the rocks below in such a way that she could pass behind the veil of water without getting wet at all.

Into this mysterious opening behind the fall Jean followed her leader, and found herself climbing a narrow dry channel through which the stream had once forced its way.  It was a hard, rough scramble up a narrow passage worn by the water and through holes almost too small to squeeze through, but at last she saw Alan’s heels just disappearing over the edge of a jutting rock and knew they were coming out into daylight again.  An instant later Alan’s head appeared in the opening, his hand reached down to help her up, and with one last effort she came out upon an open ledge and looked about her.

She could not help an exclamation of delight at what she saw.  The rock was so high that they could look out over the treetops clear to the slope where the little gray house stood.  The waterfall, plunging from a still higher level, made a barrier on one side of them, and on the other side the cliff rose, a sheer wall of rock.  Between the wall of water and the wall of rock there was a cave extending into the solid rock for a distance of about twenty feet.  There was absolutely no way of reaching this fastness except through the hidden stair, and one might wander for years through the forest and never see it at all.

“Oh,” exclaimed Jean, “it’s wonderful!  How Jock will love this place!  Don’t you believe this very cave was used by Rob Roy and his men?” and Alan, swelling with pride to think he had found it all himself, said yes, he was sure of it.

“I tell you what we’ll do,” cried Alan, a minute later.  “We’ll just leave the basket here in the cave, and when we’ve found the boys we’ll come back and have our lunch here.”

They tucked the basket away out of sight on a rocky shelf in the cave, and found their way down the steep rough stairway to the bed of the stream again and, making a wide detour, came out above the fall.  They struggled on for nearly a mile farther still without finding any trace of the boys, and were beginning to be discouraged, when they saw a break in the trees with glimpses of blue sky beyond, and a few moments later came out upon the shores of a tiny mountain lake, shining like a beautiful blue jewel in the dark setting of the pine trees on its banks.

Beyond the lake the purple peaks of higher mountains made a ragged outline against the sky.  The sun was now almost directly overhead; the waters of the lake were still, and its lovely shores were mirrored on the placid surface.  A great eagle soared in stately circles in the deep blue sky.  It was so beautiful and so still that the children stood a moment among the rocks where the tarn emptied itself into the mountain stream to look at it.

“It’s just the place for a water cow, or a horse maybe,” Jean whispered to Alan.

“Sh!” was Alan’s only reply.  He seized Jean’s hand and dragged hear down behind a rock and pointed toward the south.  There, coming out of the woods, was a beautiful stag.  It poised its noble head, and sniffed the air, as if it suspected there might be human beings about, and then stepped daintily to the lake-shore and bent to drink.  Its lips had scarcely touched the water when the children were startled by the loud report of a gun.

“Poachers,” gasped Jean, hiding her face and wishing they had never come.  “Oh, where are Jock and Sandy?” Her only thought was to make herself as small as possible and keep out of sight behind the rocks, but Alan peered through the screen of bushes which hid the rock and made violent gestures to Jean to make her look, too.  Jean crawled on her hands and knees to Alan’s side, and when she looked, what she saw made her so angry that she would have sprung to her feet if Alan had not held her down with a fierce grip.  The stag was lying by the lake-shore, and a man with the muzzle of his gun still smoking was running toward it from the woods.  The man was Angus Niel!

Jean was so astonished that for an instant she could not believe her own eyes.  The two children flattened themselves out on their stomachs and watched him pull a boat from its hiding-place among some bushes on the shore, paddle quietly to the spot where the dead stag lay, and load it swiftly into the boat.  Then he raced back to the woods again and reappeared, carrying a string of dead rabbits.  These also he crowded into the boat, and then, taking up the oars, rowed across the lake to a landing-place on the other side.  The children watched him, scarcely breathing in their excitement, until he had unloaded his game from the boat and disappeared into the woods, dragging the body of the stag after him.  In a few moments he came back for the rabbits and, having disposed of them in the same mysterious way, returned to the boat.

Then Jean exploded in a fierce whisper.  “The old thief!” she said, shaking her fist after him.  “He’s the poacher himself!  That’s why he never brings any one before the bailie, though he’s always telling about catching them at it!  And he making such a fuss because Jock chased the rabbit that was eating up our garden!  Oh, oh, oh!”

She clutched Alan and shook him in her boiling indignation.  Alan laughed and shook her back.  “I didn’t do it, you little spitfire!” he whispered, and Jean moaned, “Oh, I know it, Alan, but I can’t catch him and I’m so angry I’ve just got to do something to somebody.”

“Do you know what that old thief does?” said Alan.  “He sends that game down to the city-to Glasgow, or Edinburgh, or even London, maybe-and gets a lot of money for it!  No wonder he tells big stories to make people afraid to go into the woods.”

“I hope he won’t meet the boys,” moaned Jean.  “Jock would be sure to let his tongue loose, and then maybe he’d shoot him too!”

“Listen,” said Alan.  He gave the pewit’s call and waited.  It was answered from a point so near that they were startled.  They looked in every direction but saw nothing of the boys.

“Maybe it was a real pewit after all,” whispered Jean, but just then a tiny pebble struck Alan’s cap, and, looking around in the direction from which it came, he saw two freckled faces rise up from behind the rock on the opposite side of the spring.

“There they are,” he said, punching Jean and pointing; “they came up the other side of the burn.”  Then, making a cup of his hands, he called across the stream, “Did you see him?” The boys nodded.  “Slip back as fast as you can down that side of the burn,” Alan said, “and we’ll meet at the fall.  Wait at the foot if you get there first.  We’ve got something to show you.  Whist, and be quick, for he’ll be coming back before long, and this way like as not.”

Jock and Sandy nodded and disappeared, and Alan and Jean, springing from their hiding-place, hurried as fast as they could down their side of the stream to the trysting-place.